Realization of temperature-insensitive energy band-gap based on nanowire-well quantum systems for thermally frequency-stable laser diodes

The realization of high-power and thermally frequency-stable laser diodes is always highly desirable and also a difficulty in the areas of laser diodes and their applications. One of the major factors causing a shift in lasing frequency is the temperature dependence of the band-gap of the active medium, which leads to the photon energy changing. In this paper, we propose a novel approach and mechanism to overcome the variation in band-gap with temperature. This is the utilization of a nanowire constraint on the well in a self-organized InGaAs nanowire-well-bound quantum system. By binding relatively heat-stable nanowires directly to the well in this system, the thermal change in the energy-band of the hybrid quantum system is effectively restricted. As a result, the band-gap variations are limited to <0.01 meV K⁻¹ in a temperature range of 286-339 K for unpolarized emissions, and <0.02 meV K⁻¹ in a temperature range of 288-313 K for transverse-electric polarized emissions. The mechanism of heat-stable band-gap formation in this hybrid quantum system is analyzed in detail. This achievement is of a great significance in some advanced fields, such as atomic clocks in quantum sensing systems and optical communications.